Efron and the unlucky-in-love Swift "were deep in conversation and very giggly," a fellow diner tells the new Us Weekly of the pair, who arrived together in Efron's Audi. (Earlier in the week, the twosome supped at Pace with fellow phenom Justin Bieber.)

It's not the first time the cute duo have flirted in public. Back in 2009, Efron -- single since splitting with Vanessa Hudgens in December 2010 -- called Swift a "lovely girl, very beautiful." In turn, the Grammy-winning singer, dumped by Jake Gyllenhaal in December 2010, gushed that Efron was an "all-around amazing guy."